Flux measurements in the stable boundary layer and during morning transition
Durden, David Joseph
MetadataShow full item record
The eddy-covariance technique measures fluxes of momentum and scalars fairly accurately under well mixed convective boundary layer (daytime) conditions. However, flux measurements are not accurately measured in the stable nocturnal boundary layer (NBL) or during the morning transition time without careful analysis. The impact of gravity waves on turbulence statistics and flux calculations is shown to be significant, resulting in overestimation of turbulent kinetic energy on the order of greater 50% at times. These wave events can also modulate flux calculations rendering the results erroneous. The presence of a low-level jet can also impact turbulence structure and flux calculations. It is demonstrated the decay of a low-level jet during the morning transition can influence the transport of heat and CO2 during the morning transition. The objective of this thesis is to examine phenomena that impact these measurements and establish some quantitative estimates of the extent to which calculations are impacted.